Windwalker7

I'd doubt he'd cross a river if hit hard.

Look for any thick areas in the direction the deer was headed. Wounded deer will bed where they think they are hid. It could just be hid in a place where the weeds are a little higher.

Are you sure he hit lung and not the space between the spine and lungs?

Did you find much blood?

Did it have tiny air bubbles it it and was it bright colored?